Recently, with the continuous progress and development of electronic technology and communication technology, portable electronic devices occupying little space, for example, a cellular phone, a personal digital assistant (PDA) have been proposed. Almost all the portable electronic devices available on the market are integrated with various functions to improve the competitiveness thereof. In addition to the common photographing, calling, and internet browsing functions, a global positioning system (GPS) or other positioning systems, an electronic map, and a navigation system are further integrated in a current handheld communication apparatus. Accordingly, a user may obtain the self location through the positioning system at any time and any place, and finds out an optimal route through the planning and guiding of the navigation system to arrive at the destination.
The electronic map may be combined with the GPS or other positioning systems, such that the user can know a relative relation between the current location and the location of the destination. Specifically, the user First loads the electronic map into the electronic device, and then selects or inputs desired destinations or point of interests (POIs) through a touch screen, a keyboard, or other input devices of the electronic device, such that the electronic device displays the locations of the destinations or POIs on the electronic map.
However, since the size of the screen of the electronic device is limited, the electronic device usually can only display the electronic map on a suitable scale. Therefore, the electronic device can display only a certain area of the electronic map on the screen, for example, an area currently browsed by the user or an area around a certain POI. Under such a situation, if the user intends to check POIs dispersed outside the displayed area, many times of operations of zooming in, zooming out, map panning, map changing, and/or complicated menu selecting operations must be performed to show the POIs on the map, which is rather time-consuming and inconvenient. In addition, if the user intends to check the relative location among the POIs on the electronic map, the scale or the area of the electronic map must be adjusted to a suitable scale for displaying all the POIs on the same displayed area. The complicated operations are not only time-consuming, but also inconvenient for the user.